Rs 1 Crore Retirement Target: How much extra SIP is needed if expected return falls from 12% to 9%?

If you are planning your retirement corpus through a systematic investment plan (SIP), then you have to focus on two main factors -- how much you invest every month and the return your investment earns over the years. Many investors calculate their future corpus assuming an annual return of 12 per cent from equity mutual funds. But returns from market-linked investments are not fixed. What if the actual return is only 9 per cent?

A lower return can make a big difference to the monthly SIP needed to reach the same retirement goal.

Let us take a simple example. Suppose an investor has 20 years left for retirement and wants to build a corpus of Rs 1 crore. We will compare the SIP required at assumed annual returns of 12 per cent and 9 per cent.

Suppose you get an average annual return of 12 per cent over 20 years; the investor would need to invest around Rs 10,109 every month to build a corpus of Rs 1 crore. Check calculations below:

Over 20 years, the investor would make 240 monthly investments.

Monthly SIP: Around Rs 10,109

Investment period: 20 years

Total amount invested: Around Rs 24.26 lakh

Estimated corpus: Rs 1 crore

The remaining amount comes from the returns generated by the investments over the long period.

Now let's assume the investment earns only nine per cent annually instead of 12 per cent. Now, if we calculate to achieve Rs 1 crore target, the monthly SIP would have to increase to around Rs 14,973 for 20 years. This means an investor would need to invest close to Rs 15,000 every month. Check calculations below:

Monthly SIP: Around Rs 14,973

Investment period: 20 years

Total amount invested: Around Rs 35.93 lakh

Estimated corpus: Rs 1 crore

The retirement target remains unchanged, but because the expected return is lower, the investor has to contribute more from his or her own pocket.

This means the investor needs to increase the monthly contribution by nearly Rs 4,900 to make up for the lower expected return. In percentage terms, the required SIP rises by about 48 per cent. The extra contribution works out to around Rs 58,000 a year.

Over the full 20-year period, the investor would contribute around Rs 11.67 lakh more when the expected return falls from 12 per cent to 9 per cent.

A difference of three percentage points may not appear very large in one year. But over 20 years, compounding can make the impact much bigger.

At 12 per cent, the money grows faster, and returns generated in the early years also get more time to earn further returns.

At 9 per cent, the same compounding process happens at a slower rate. As a result, the investor has to put in more money every month to reach the same final amount.

This is also why retirement planning should not depend only on an optimistic return assumption.

Investors may consider using slightly conservative return assumptions while planning long-term goals.

In this example, a Rs 1 crore target over 20 years needs around Rs 10,100 a month at 12 per cent returns. If expected returns fall to 9 per cent, the requirement rises to nearly Rs 15,000.

The calculation shows that when returns are lower, investors generally have two choices -- invest more or give the investment more time.

These are only illustrations. Mutual fund returns are market-linked and are not guaranteed. Actual returns may be higher or lower, and investors should plan according to their financial goals, risk capacity, and time available before retirement.